Benefit of Large Thighs – Study

There is a lot of interest swirling around the study that showed a larger thigh circumference may add years to one’s life.

To start, I want to remind everyone that the strongest predictor of your lifespan is the various lifespans of your parents, siblings, and grandparents.

To continue, I wanted to first link to the full text of the study itself. Please take a little time to read through this, take a look at the graphs, think about how the sampling changes based on what is being looked at (in other words, sometimes the author is only talking about the group of people who died during the study period, which instead of 3000 people, is closer to 300).

Another point is how the study is being marketed. A great example is this “caveat” tacked on to the end of an MSNBC article:

She was quick to add, however, that the study should not be interpreted as a free pass for people who want to skip the gym. In this case, much bigger was not better. The protective benefits of heftier thighs didn’t rise when thighs grew larger than 60 centimeters. “There’s no further advantage there,” Heitmann said.

This is the usual media/study author obesity-study-lie-by-omission (can’t give those fatties any reason not to loathe themselves, or for thinner people not to loathe the fatties). If you look at the charts in the original study, you’ll notice that though the supposed benefit is maximized at a thigh circumference of 60 cm, there is no marked decrease of benefit with larger thigh circumference. That is, at 70 cm one enjoys every bit of the benefit enjoyed at 60 cm.

However, I encourage you to come to your own conclusions about this study, based on the text itself. The text author is an out-and-out obesity researcher: his bread and butter is trying to show correlations to health indices based on weight, BMI, body fat, etc (just do a search for his name and institution on Google Scholar).

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2 comments on “Benefit of Large Thighs – Study”

Thank you for the link to the study.
Here are some things that jump out at me:
“Similar findings [regarding survival advantage] were seen for the women, though not significantly so for BMI, percentage body fat, hip and waist circumference, and alcohol consumption.” So for women, age, blood pressure, and lipid concentrations, as well as pack years and prevalence of smokers, and inactivity were generally lower for the women who survived, whereas baseline fat free mass, thigh circumference, and height were greater for the survivors. BUT NOT BMI, PERCENTAGE BODY FAT, HIP AND WAIST CIRCUMFERENCE.

The editorial in the BMJ asks this question about the link to larger thighs: “The results raise several questions. Is this association real and independent, or a spurious or chance finding?” Which I think is always a good question, and they say the stats look good to them.

The editorial asks: “Is this association biologically plausible? It would seem logical that having bigger thighs would be a reflection of greater adiposity, and that this would increase the risk of heart disease. However, the authors cite studies suggesting that too little muscle or subcutaneous fat (or both) in the lower limbs may predispose to adverse glucose and lipid metabolism.”

Again, the “obesity paradox” — how could fatter possibly be better? And yet, to my mind, it’s entirely believable that a heavier and active older person may in fact be at lower risk of many of the diseases associated with death in older people, better ability to recover from illness, more bone density, and many other things.

What’s infuriating is that the mounting evidence doesn’t lead to any change in the paradigm. There’s no, “if you are older and active and have fat on your body, relax! Stop worrying! Eat well, live life, enjoy!” Instead, there’s this quest to see if wrist circumference or calf density or elbow wrinkling or pinkie cuticle depth are indicative of early death. Bizarre. It appears that the study’s authors ended up disproving their hyptothesis, they were probably setting out to prove that having a smaller waist circumference but large thighs put you at greater risk — but ended up with the opposite finding. Instead of rejoycing — O how glorious the human form in it’s diversity — they begrudgingly admit that having a small thigh circumference might not be a great thing, if it means much of anything at all. Again, the BMJ editorial says this: “Will this association help clinicians predict risk in individual patients more accurately than they already do using readily accessible and validated risk calculators? The answer is—we do not know. To improve individual risk estimates beyond those that we can derive now, the hazard ratios would need to be much larger than those seen in this study. ”

Even though this result is kind of fat-friendly, isn’t it time, also, to question the emphasis of researchers to find visible indicators like this. What is the motivation of for that? Are the real tests (for high cholestrol, blood pressure etc) too expensive?
Or do they want to support the overconfidence of doctors to decide what they will telll you just by glancing at a patient when she walks into the room?